This invention relates to an improved carton for heating food products in a microwave oven, and more specifically to a carton of this type with integral vent means for permitting the release of mositure during heating.
In U.S. Pat. No. 3,876,131 and U.S. Pat. No. 29,185, it was recognized that packages useful for heating foods by microwave ovens must be vented to permit exhaustion of moisture vapors generated during the heating process, but yet must be sealed for protection of the food during shipment and storage. To meet these criteria, these patents disclose placing apertures in the bottom of the carton and covering these with a strip of film which could be removed prior to heating.
It was also found important to elevate the bottom surface of the carton from the microwave oven shelf so that the moist gases could be efficiently exhausted from the container. This requirement was met by provision of side wall panels which extended downwardly below the plane of the bottom surface of the container. In effect, the side walls formed legs which rasied the container above the support surface.
While the provision of vent holes and downwardly extending side walls did provide efficient exhaustion of gases from the container, there are certain product applications where open vent holes, even when covered with a strip of moisture barrier film, are disadvantageous from either the aesthetic or the protective viewpoint. Thus, it would be advantageous to provide a carton which enabled efficient venting, but which did not require the removal of portions of the container's structural wall prior to the time of heating.
Moreover, because of the ease and convenience of cooking in microwave ovens, consumers are frequently disposed to heat individual-sized portions of food for themselves where, previously, dishes of that nature would not be cooked individually due to the trouble and expense associated with heating a conventional convection oven. However, it is frequently desirable, when packaging foods for use in microwave ovens, to provide separable portions so that they can be cooked individually or as a group. Thus, it would be advantageous to provide a multi-unit package which is especially suited for heating the contents of either one or all of the compartments at the same time in a microwave oven.